When you're stood drying your freshly cleaned hands off in the pub toilet and someone walks out without washing theirs, you probably feel like you're one-upping them in the hygiene stakes.
However, a study conducted by the University of Connecticut now suggests that this may not be the case after all.
The research showed that bathroom hand dryers like to suck in pathogens and spray them back out when people use them.
To put that simply: the hand dryer is probably spraying you with other people's shit. Nice.
The findings match up with those from previous studies that have found hand dryers can spray germs into the air.
However, while some earlier studies were rumoured to have been funded by the paper towel industry, this new one clearly demonstrates that even low-powered dryers are capable of spraying germs all over the place.
The study claimed that the results could be of concern for hospitals as it may mean that pathogens could be transferred more easily from room to room.
The paper read: "This study has implications for the control of opportunistic bacterial pathogens and spores in public environments including health care settings.
"Within a large building, potentially pathogenic bacteria, including bacterial spores, may travel between rooms, and subsequent bacterial/spore deposition by hand dryers is a possible mechanism for spread of infectious bacteria, including spores of potential pathogens if present."
The science is pretty basic.
Once a toilet is flushed with a lid open, bacteria is thrown up into the air. That bacteria is then sucked in through the air intake on the dryer, heated up and then sprayed onto the user once switched on.
The research took place in the bathrooms at the University of Connecticut.
In one case, the researchers placed plates of agar media (gelled bacteria food) for two minutes in bathrooms with dryers off.
In another case, the bacteria were blasted with dryer air for 30 seconds, keeping them at 12 inches away from the nozzle.
In the first instance, the researchers caught zero to one colonies of bacteria per plate. While the same plates showed 18 to 60 colonies when the blowers were turned on for 30 seconds.
The researchers said: "One reason hand dryers may disperse so many bacteria is the large amount of air that passes through hand dryers, 19,000 linear feet/min at the nozzle.
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"The convection generated by high airflow below the hand dryer nozzles could also draw in room air."
So, next time you find yourself in a public toilet, you may just want to wipe your hands on your jeans.
Featured Image Credit: Mike Mozart/Creative CommonsTopics: Science, Community, Weird, Health